Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Amazon CloudFront controls

These controls are related to CloudFront resources.

These controls may not be available in all Amazon Web Services Regions. For more information, see Availability of controls by Region.

[CloudFront.1] CloudFront distributions should have a default root object configured

Related requirements: NIST.800-53.r5 SC-7(11), NIST.800-53.r5 SC-7(16)

Category: Protect > Secure access management > Resources not publicly accessible

Severity: High

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-default-root-object-configured

Schedule type: Change triggered

Parameters: None

This control checks whether an Amazon CloudFront distribution is configured to return a specific object that is the default root object. The control fails if the CloudFront distribution does not have a default root object configured.

A user might sometimes request the distribution's root URL instead of an object in the distribution. When this happens, specifying a default root object can help you to avoid exposing the contents of your web distribution.

Remediation

To configure a default root object for a CloudFront distribution, see How to specify a default root object in the Amazon CloudFront Developer Guide.

[CloudFront.3] CloudFront distributions should require encryption in transit

Related requirements: NIST.800-53.r5 AC-17(2), NIST.800-53.r5 AC-4, NIST.800-53.r5 IA-5(1), NIST.800-53.r5 SC-12(3), NIST.800-53.r5 SC-13, NIST.800-53.r5 SC-23, NIST.800-53.r5 SC-23(3), NIST.800-53.r5 SC-7(4), NIST.800-53.r5 SC-8, NIST.800-53.r5 SC-8(1), NIST.800-53.r5 SC-8(2), NIST.800-53.r5 SI-7(6)

Category: Protect > Data Protection > Encryption of data-in-transit

Severity: Medium

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-viewer-policy-https

Schedule type: Change triggered

Parameters: None

This control checks whether an Amazon CloudFront distribution requires viewers to use HTTPS directly or whether it uses redirection. The control fails if ViewerProtocolPolicy is set to allow-all for defaultCacheBehavior or for cacheBehaviors.

HTTPS (TLS) can be used to help prevent potential attackers from using person-in-the-middle or similar attacks to eavesdrop on or manipulate network traffic. Only encrypted connections over HTTPS (TLS) should be allowed. Encrypting data in transit can affect performance. You should test your application with this feature to understand the performance profile and the impact of TLS.

Remediation

To encrypt a CloudFront distribution in transit, see Requiring HTTPS for communication between viewers and CloudFront in the Amazon CloudFront Developer Guide.

[CloudFront.4] CloudFront distributions should have origin failover configured

Related requirements: NIST.800-53.r5 CP-10, NIST.800-53.r5 SC-36, NIST.800-53.r5 SC-5(2), NIST.800-53.r5 SI-13(5)

Category: Recover > Resilience > High availability

Severity: Low

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-origin-failover-enabled

Schedule type: Change triggered

Parameters: None

This control checks whether an Amazon CloudFront distribution is configured with an origin group that has two or more origins.

CloudFront origin failover can increase availability. Origin failover automatically redirects traffic to a secondary origin if the primary origin is unavailable or if it returns specific HTTP response status codes.

Remediation

To configure origin failover for a CloudFront distribution, see Creating an origin group in the Amazon CloudFront Developer Guide.

[CloudFront.5] CloudFront distributions should have logging enabled

Related requirements: NIST.800-53.r5 AC-2(4), NIST.800-53.r5 AC-4(26), NIST.800-53.r5 AC-6(9), NIST.800-53.r5 AU-10, NIST.800-53.r5 AU-12, NIST.800-53.r5 AU-2, NIST.800-53.r5 AU-3, NIST.800-53.r5 AU-6(3), NIST.800-53.r5 AU-6(4), NIST.800-53.r5 CA-7, NIST.800-53.r5 SC-7(9), NIST.800-53.r5 SI-3(8), NIST.800-53.r5 SI-4(20), NIST.800-53.r5 SI-7(8)

Category: Identify > Logging

Severity: Medium

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-accesslogs-enabled

Schedule type: Change triggered

Parameters: None

This control checks whether server access logging is enabled on CloudFront distributions. The control fails if access logging is not enabled for a distribution.

CloudFront access logs provide detailed information about every user request that CloudFront receives. Each log contains information such as the date and time the request was received, the IP address of the viewer that made the request, the source of the request, and the port number of the request from the viewer.

These logs are useful for applications such as security and access audits and forensics investigation. For additional guidance on how to analyze access logs, see Querying Amazon CloudFront logs in the Amazon Athena User Guide.

Remediation

To configure access logging for a CloudFront distribution, see Configuring and using standard logs (access logs) in the Amazon CloudFront Developer Guide.

[CloudFront.6] CloudFront distributions should have WAF enabled

Related requirements: NIST.800-53.r5 AC-4(21)

Category: Protect > Protective services

Severity: Medium

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-associated-with-waf

Schedule type: Change triggered

Parameters: None

This control checks whether CloudFront distributions are associated with either Amazon WAF Classic or Amazon WAF web ACLs. The control fails if the distribution is not associated with a web ACL.

Amazon WAF is a web application firewall that helps protect web applications and APIs from attacks. It allows you to configure a set of rules, called a web access control list (web ACL), that allow, block, or count web requests based on customizable web security rules and conditions that you define. Ensure your CloudFront distribution is associated with an Amazon WAF web ACL to help protect it from malicious attacks.

Remediation

To associate an Amazon WAF web ACL with a CloudFront distribution, see Using Amazon WAF to control access to your content in the Amazon CloudFront Developer Guide.

[CloudFront.7] CloudFront distributions should use custom SSL/TLS certificates

Related requirements: NIST.800-53.r5 AC-17(2), NIST.800-53.r5 AC-4, NIST.800-53.r5 IA-5(1), NIST.800-53.r5 SC-12(3), NIST.800-53.r5 SC-13, NIST.800-53.r5 SC-23, NIST.800-53.r5 SC-23(3), NIST.800-53.r5 SC-7(4), NIST.800-53.r5 SC-8, NIST.800-53.r5 SC-8(1), NIST.800-53.r5 SC-8(2), NIST.800-53.r5 SI-7(6)

Category: Protect > Data Protection > Encryption of data-in-transit

Severity: Medium

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-custom-ssl-certificate

Schedule type: Change triggered

Parameters: None

This control checks whether CloudFront distributions are using the default SSL/TLS certificate CloudFront provides. This control passes if the CloudFront distribution uses a custom SSL/TLS certificate. This control fails if the CloudFront distribution uses the default SSL/TLS certificate.

Custom SSL/TLS allow your users to access content by using alternate domain names. You can store custom certificates in Amazon Certificate Manager (recommended), or in IAM.

Remediation

To add an alternate domain name for a CloudFront distribution using a custom SSL/TLS certificate, see Adding an alternate domain name in the Amazon CloudFront Developer Guide.

[CloudFront.8] CloudFront distributions should use SNI to serve HTTPS requests

Related requirements: NIST.800-53.r5 CA-9(1), NIST.800-53.r5 CM-2

Category: Protect > Secure network configuration

Severity: Low

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-sni-enabled

Schedule type: Change triggered

Parameters: None

This control checks if Amazon CloudFront distributions are using a custom SSL/TLS certificate and are configured to use SNI to serve HTTPS requests. This control fails if a custom SSL/TLS certificate is associated but the SSL/TLS support method is a dedicated IP address.

Server Name Indication (SNI) is an extension to the TLS protocol that is supported by browsers and clients released after 2010. If you configure CloudFront to serve HTTPS requests using SNI, CloudFront associates your alternate domain name with an IP address for each edge location. When a viewer submits an HTTPS request for your content, DNS routes the request to the IP address for the correct edge location. The IP address to your domain name is determined during the SSL/TLS handshake negotiation; the IP address isn't dedicated to your distribution.

Remediation

To configure a CloudFront distribution to use SNI to serve HTTPS requests, see Using SNI to Serve HTTPS Requests (works for Most Clients) in the CloudFront Developer Guide.

[CloudFront.9] CloudFront distributions should encrypt traffic to custom origins

Related requirements: NIST.800-53.r5 AC-17(2), NIST.800-53.r5 AC-4, NIST.800-53.r5 IA-5(1), NIST.800-53.r5 SC-12(3), NIST.800-53.r5 SC-13, NIST.800-53.r5 SC-23, NIST.800-53.r5 SC-23(3), NIST.800-53.r5 SC-7(4), NIST.800-53.r5 SC-8, NIST.800-53.r5 SC-8(1), NIST.800-53.r5 SC-8(2), NIST.800-53.r5 SI-7(6)

Category: Protect > Data Protection > Encryption of data-in-transit

Severity: Medium

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-traffic-to-origin-encrypted

Schedule type: Change triggered

Parameters: None

This control checks if Amazon CloudFront distributions are encrypting traffic to custom origins. This control fails for a CloudFront distribution whose origin protocol policy allows 'http-only'. This control also fails if the distribution's origin protocol policy is 'match-viewer' while the viewer protocol policy is 'allow-all'.

HTTPS (TLS) can be used to help prevent eavesdropping or manipulation of network traffic. Only encrypted connections over HTTPS (TLS) should be allowed.

Remediation

To update the Origin Protocol Policy to require encryption for a CloudFront connection, see Requiring HTTPS for communication between CloudFront and your custom origin in the Amazon CloudFront Developer Guide.

[CloudFront.10] CloudFront distributions should not use deprecated SSL protocols between edge locations and custom origins

Related requirements: NIST.800-53.r5 AC-17(2), NIST.800-53.r5 AC-4, NIST.800-53.r5 IA-5(1), NIST.800-53.r5 SC-12(3), NIST.800-53.r5 SC-13, NIST.800-53.r5 SC-23, NIST.800-53.r5 SC-7(4), NIST.800-53.r5 SC-8, NIST.800-53.r5 SC-8(1), NIST.800-53.r5 SC-8(2), NIST.800-53.r5 SI-7(6)

Category: Protect > Data Protection > Encryption of data-in-transit

Severity: Medium

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-no-deprecated-ssl-protocols

Schedule type: Change triggered

Parameters: None

This control checks if Amazon CloudFront distributions are using deprecated SSL protocols for HTTPS communication between CloudFront edge locations and your custom origins. This control fails if a CloudFront distribution has a CustomOriginConfig where OriginSslProtocols includes SSLv3.

In 2015, the Internet Engineering Task Force (IETF) officially announced that SSL 3.0 should be deprecated due to the protocol being insufficiently secure. It is recommended that you use TLSv1.2 or later for HTTPS communication to your custom origins.

Remediation

To update the Origin SSL Protocols for a CloudFront distribution, see Requiring HTTPS for communication between CloudFront and your custom origin in the Amazon CloudFront Developer Guide.

[CloudFront.12] CloudFront distributions should not point to non-existent S3 origins

Related requirements: NIST.800-53.r5 CM-2, NIST.800-53.r5 CM-2(2)

Category: Identify > Resource configuration

Severity: High

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-s3-origin-non-existent-bucket

Schedule type: Periodic

Parameters: None

This control checks whether Amazon CloudFront distributions are pointing to non-existent Amazon S3 origins. The control fails for a CloudFront distribution if the origin is configured to point to a non-existent bucket. This control only applies to CloudFront distributions where an S3 bucket without static website hosting is the S3 origin.

When a CloudFront distribution in your account is configured to point to a non-existent bucket, a malicious third party can create the referenced bucket and serve their own content through your distribution. We recommend checking all origins regardless of routing behavior to ensure that your distributions are pointing to appropriate origins.

Remediation

To modify a CloudFront distribution to point to a new origin, see Updating a distribution in the Amazon CloudFront Developer Guide.

[CloudFront.13] CloudFront distributions should use origin access control

Category: Protect > Secure access management > Resource not publicly accessible

Severity: Medium

Resource type: AWS::CloudFront::Distribution

Amazon Config rule: cloudfront-s3-origin-access-control-enabled

Schedule type: Change triggered

Parameters: None

This control checks whether an Amazon CloudFront distribution with an Amazon S3 origin has origin access control (OAC) configured. The control fails if OAC isn't configured for the CloudFront distribution.

When using an S3 bucket as an origin for your CloudFront distribution, you can enable OAC. This permits access to the content in the bucket only through the specified CloudFront distribution, and prohibits access directly from the bucket or another distribution. Although CloudFront supports Origin Access Identity (OAI), OAC offers additional functionality, and distributions using OAI can migrate to OAC. While OAI provides a secure way to access S3 origins, it has limitations, such as lack of support for granular policy configurations and for HTTP/HTTPS requests that use the POST method in Amazon Web Services Regions that require Amazon Signature Version 4 (SigV4). OAI also doesn't support encryption with Amazon Key Management Service. OAC is based on an Amazon best practice of using IAM service principals to authenticate with S3 origins.

Remediation

To configure OAC for a CloudFront distribution with S3 origins, see Restricting access to an Amazon S3 origin in the Amazon CloudFront Developer Guide.

[CloudFront.14] CloudFront distributions should be tagged

Category: Identify > Inventory > Tagging

Severity: Low

Resource type: Amazon::CloudFront::Distribution

Amazon Config rule:tagged-cloudfront-distribution (custom Security Hub rule)

Schedule type: Change triggered

Parameters:

This control checks whether an Amazon CloudFront distribution has tags with the specific keys defined in the parameter requiredTagKeys. The control fails if the distribution doesn’t have any tag keys or if it doesn’t have all the keys specified in the parameter requiredTagKeys. If the parameter requiredTagKeys isn't provided, the control only checks for the existence of a tag key and fails if the distribution isn't tagged with any key. System tags, which are automatically applied and begin with aws:, are ignored.

A tag is a label that you assign to an Amazon resource, and it consists of a key and an optional value. You can create tags to categorize resources by purpose, owner, environment, or other criteria. Tags can help you identify, organize, search for, and filter resources. Tagging also helps you track accountable resource owners for actions and notifications. When you use tagging, you can implement attribute-based access control (ABAC) as an authorization strategy, which defines permissions based on tags. You can attach tags to IAM entities (users or roles) and to Amazon resources. You can create a single ABAC policy or a separate set of policies for your IAM principals. You can design these ABAC policies to allow operations when the principal's tag matches the resource tag. For more information, see What is ABAC for Amazon? in the IAM User Guide.

Remediation

To add tags to a CloudFront distribution, see Tagging Amazon CloudFront distributions in the Amazon CloudFront Developer Guide.